Two engine options are to be offered in a new automobile model. Engine A is naturally aspirated with a compression ratio of 10.5:1 and cylinder inlet conditions of 60°C and 96 kPa. Engine B is...

Two engine options are to be offered in a new automobile model. Engine A is naturally aspirated with a compression ratio of 10.5:1 and cylinder inlet conditions of 60°C and 96 kPa. Engine B is supercharged with aftercooling and has cylinder inlet conditions of 80°C and 130 kPa. To avoid knock problems, it is desirable to have the air–fuel temperature at the start of combustion in engine B be the same as in engine A.

Calculate:

(a) Temperature at start of combustion in engine A, using air-standard Otto cycle analysis. [°C]

(b) Compression ratio of engine B that would give the same temperature at the start of combustion.

(c) Temperature reduction in the aftercooler of engine B if the compressor has an isentropic efficiency of 82% and inlet conditions are the same as in engine A. [°C]